#include<iostream>
#include<iomanip>
#include<algorithm>
using namespace std;

double a[10010];
int n, k;

bool check(int x)
{
	int cnt = 0;
	for(int i = 1;i <= n;i++)
		cnt += a[i]/x;
	if(cnt >= k)
		return true;
	else
		return false;
}

int main()
{
	cin>>n>>k;
	for(int i = 1;i <= n;i++)
	{
		cin>>a[i];
		a[i] *= 100;
	}
		
	int l = 1, r = *max_element(a+1, a+n+1), mid;
	while(l <= r)
	{
		mid = (l+r)/2;
		if(check(mid))
			l = mid + 1;
		else
			r = mid - 1;
	}
	cout<<fixed<<setprecision<<(int)(l+0.5)/100;
	return 0;
}

